Method and apparatus for processing yarn



Sept. 26, 1961 c. G. EVANS 3,001,355

METHOD AND APPARATUS FOR PROCESSING YARN Filed June 8, 1959 TO EMF SOURCF |5b INVENTOR.

CYRIL G. EVANS ATTORNEY 3,001,355 METHOD AND APPARATUS'FOR PROCESSING YARN Cyril G. Evans, Clemson, S.C., assignor to Deering Milliken Research Corporation, Pendleton, S.C., a corporation of Delaware Filed June 8, 1959, Ser. No. 818,658 7 Claims. (CI. 57-34) This invention relates to the production of a crinkled or crimped yarn and is particularly applicable to yarn composed in whole or in part of thermoplastic filaments, such as hexamethylene adipamide (e.g. nylon), polyethylene terephthalate (e.g. Dacron), etc.

In one previous method employed for producing a crinkled yarn, a false twist is imparted to a bundle of thermoplastic filaments after passing these filaments through a heating medium, permitting the twist to run backward into the heating medium to a twist arresting point in the area of the heating medium, the twist being taken out upon passage of the bundle beyond and on the opposite side of the false twister device.

The present invention provides an improved method and apparatus for forming a highly useful crinkled yarn, wherein the yarn in the form of a single continuous ther moplastic filament or a plurality of substantially parallel filaments, is fed through a heating zone to a temperature between the first and second order transition points for the particular yarn, and is subsequently fed to a twisterwinder takeup, the real twist imparted by the twisterwinder takeup being permitted to run back into the zone where the yarn is at a temperature between the first and second order transition points to a twist stop or arrestor means such as a roller, whereby the torque resulting from the twist inserted by the twister-winder takeup will be concentrated in a very short length of yarn on the output side of the twist arrestor device and will thus cause a relative higher apparent twist to be set in the yarn than that which would result merely from the twist inserted by the takeup without permitting such to run back into this hot yarn zone. Since the yarn is maintained at a temperature between the first and second order transition points for only a short distance (e.g. /2 inch-2 inches or the like) beyond the twist arrestor device, it will be apparent that by making the distance between the twist arrestor device and the twister-winder considerably longer than this short distance, the twist inserted by the twisterwinder takeup over this entire length of yarn will be concentrated in substantially this small yarn length of /2 inch or so, thereby resulting in a very high apparent twist being fed into the yarn through the use of a relative low twister-winder takeup. Contra to the prior method described above, it will be noted that according to the present invention the twist is not inserted by a false twisting device and not subsequently taken out of the yarn, but is retained as it is wound onto the takeup package. This is an important distinction,'in that the resultant yarn has a considerably higher apparent and eifective twist therein, and further, is of additional importance in the present invention may be practiced merely by applying a heating means of suitable type for a twist arrestor to a conventional twister-winder arrangement. Thus, there is not only an improved product produced by the present method, but the present method also affords a much greater ease of application and broader utility than the various prior art methods.

The invention will be better understood from the following detailed description of one embodiment thereof, taken in conjunction with accompanying drawing, in which FIGURE 1 is a diagrammatic view of one physical embodiment of the invention, and

States Patent ice FIGURE 2 is a further diagrammatic illustration in enlarged view of the heating and the twist arrest zones of the apparatus of FIGURE 1.

Referring to the drawing, a yarn Y composed of nylon, Dacron, or other thermoplastic material, in either monofilament or multi-filament form is fed from a supply source such as a bobbin or cone 11 over a bar guide 12, through a pigtail guide 13, and then through a heating Zone which in the present embodiment takes the form of the hot peripheral surface of an electrically heated roll 15a of a pair of nip rolls 15a and 15b. The roll 15a may be heated as by a resistance heater disposed therein, as indicated schematically at 15:1 The yarn Y may be wrapped about the heated roll 15 one or more times if desired in order to achieve sufiicient heat exchange and to raise the temperature of the yarn to the desired level which, as stated supra, is above the second order transition point (approximately F. for nylon and Dacron) for the yarn and below the first order transition point. (which is ap proximately 418 F. for nylon and Dacron). The yarn may be passed through an aligning guide 17 if desired and is then progressed to a suitable twister-winder takeup 19 which may be and is preferably a conventional twisterwinder takeup construction such as a ring and traveler twister, as shown, or a two-for-one twister or the like.

It is of importance that the guide 17 be so constructed and :arranged that it does not aiford any substantial impediment to the running of the twist backward into the first-to-second-order-transition-point temperature zone adjacent the heater roll 15. This may be readily accomplished by arranging this guide on the axis of the twisterwinder takeup device 19 and making the guide eye of a diameter substantially larger than the yarn.

.It will be noted that the heater roll 15a of the nip roll pair in the present embodiment serves not only to heat the yarn to the desired temperature but also serves as a twist arrestor in conjunction with the roll 15b, whereby the twist imparted by the twister-winder is concentrated in a small length of the yarn passing from the output side of the heat roll 15. It is of importance that by passing the yarn through and directly tangentially from the nip of rolls 15a and 151) the fed-back twist is positively blocked at the nip, and the resulting torsional forces on the yarn are more highly concentrated in a shorter length of the critically heated yarn than would be possible if a single heating roll were employed, with the twist running partly back over the peripheral surface of the heater roll. It is also desirable that the nip rolls, or at least the heater roll 15a, be relatively small (e.g. /2-1 inch in diameter) so as to permit the yarn to cool sufiiciently fast after leaving the twist arresting zone as to afford a desirably short critically heated length proceecb ing from the nip.

An important advantage of the invention is derived from the fact that a large amount of the twist tendency imparted to the yarn is in latent form (prior to post development thereof), and in order to develop the whole of the twist the yarn must be reheated to above the second order transition point as by contact with a heated surface, immersion in hot water, hot air, or other suitable heating arrangement. Thus, the yarn is relatively docile during knitting, weaving, or the like operations, it not post-heat-treated prior thereto and may be made to develop its full torque and resultant twist during the finishing of the fabric.

While in the preferred embodiment the heater for the yarn also serves as the twist arrestor, it will be apparent that other heating devices may be employed, and other twist arresting devices, as a part of the heater or separate from the heater, may be employed. The essential point is that the yarn be heated in an area where the real twist from the twister-winder takeup is permitted to run freely back under tension into the heated zone and wherein this twist is arrested such that a relatively small length of yarn at a temperature between the first and second order transition points is disposed on the outflow side of the twist arresting device, whereby the twist inserted by the twister-winder takeup is concentrated in this relatively small length of yarn.

While only one embodiment of the invention has been specifically illustrated and described herein, it will be apparent to those skilled in the art that many modifications may be made without departing from the scope and spirit of the invention. Accordingly, it will be under stood that the invention is not to be limited by the illusi a a 4 3. Apparatus for producing crinkled thermoplastic yarn comprising yarn supply means, heating means in sequential flow relation to said yarn supply means and adapted to heat the thermoplastic yarn proceeding from said supply means to a temperature between the first and second order transition points of said yarn, twister-winder takeup means in sequential flow relation to said heating means, and a twist arrestor disposed in the vicinity of said heating means and being adapted to arrest the twist feeding backwardly from said twister-winder takeup means, and means feeding said yarn from said twist arrestor to said twister-winder takeup means in a substan- 'tially unconfined path whereby the twist in said yarn can trative embodiment specifically described and shown herein, but onlyby the scope of the appended claims.

That which is claimed is: 1. The method of producing a textured yarn comprising passing a thermoplastic substantially continuous filat ment yarn from a supply source through a heating zone and past a substantially abrupt twist arresting point to a twister-winder takeup device, heating said yarn in said heating zone to a temperature such that the temperature of said yarn on the outflow side of said twist arresting I twister-winder takeup, and permitting the real twist to freely feed backwardly substantially unimpededly into said relatively short length of yarn adjacent to said twist arresting point and maintaining said relatively short length of yarn free and unrestricted in immediate subsequent flow relation adjacent said twist arresting point.

2. The method according to claim 1 further comprising subsequently re-exposing said yarn to a temperature between the first and second, order transition points for said yarn in order to develop the full latent twist imparted to said yarn by the feed back of the twist into said relatively short lengths of yarn while said relatively short lengths of yarn are initially at a temperature between the first and second order transition points.

freely feed backwardly from said twister-winder takeup means to the output side of said twist arrestor, said twist arrestor comprising a pair of nip rolls, the paths of said yarn as it leaves said nip rolls being substantially tangential to the nip surface of both of said nip rolls.

4. Apparatus according to claim 3 wherein said nip is in substantially vertical alignment with the axis of said twister-winder takeup means.

5. The method according to claim 1 wherein said yarn is hexamethylene adipamide.

6. The method according to claim 1 wherein said yarn is polyethylene terephthalate.

7. The method according to claim 1 wherein said yarn is passed through the nip of a pair of nip rolls, said nip forming said twist arresting point, and wherein said yarn proceeds from the nip of said nip rolls in a straight unimpeded line including said relatively short length of yarn maintained at a temperature between the first and second order of transition points for the yarn and in which the back twist is concentrated.

References Cited in the file of this patent UNITED STATES PATENTS 2,130,247 Parker Sept. 13, 1938 2,202,031 Smith May 28, 1940 2,336,100 Jacque Dec. 7, 1943 

